We remember where we were when it happened: It was a windy fall day in San Francisco -- we got off BART and took the escalator up to the Civic Center. We walked across the lawn towards City Hall and there was the mkLotus. That was the moment we fell in love with Michelle Kaufmann's green prefab homes.

We'd never been inside of one before; we'd only seen pictures.

Inside, Kaufmann's homes are bright, open, beautiful spaces. (Get yourself to the opening of her new mkSolaire at Chicago's Museum of Science and Industry, if you don't believe us.) And, her very own Glidehouse in Novato, Ca, where she lives with her husband Kevin and her dogs Otis and Peekay, is no exception.

Kaufmann was kind enough to send us photos of her home as well as answer a number of our prying questions.

When I was designing the first Glidehouse, which is the house I live in today, I was influenced by Japanese homes, along with Eichler and Eames, as well as the rural farm buildings from my childhood in Iowa.

What was the inspiration for your home?:

Basically, my husband, Kevin Cullen, and I were just looking for a place to live in the Bay Area. The most frustrating six months of my life! Always being disappointed by what was available and shocked by the prices – "$600,000 for a one bedroom fixer-upper! Move fast! This deal won't last!" We were just about to give up when we thought about the possibility of building a home. That is when I started designing our small, modern, sustainable house.

We designed it not for how it looks, but how it functions. We wanted it to not cost a lot (we didn't have a huge budget); we wanted a really low energy bill (again, not a huge amount of money, so we wanted a zero energy bill), we wanted to make the house feel larger than it is, so we went with the approach of "design big, rather than build big"; we wanted to design the home to not require air conditioning (I just hate the air quality from air conditioners), we wanted to not have to turn on lights during the day; we wanted the space to feel clean, so we needed a super smart storage system to incorporate our "stuff"; we wanted to be as efficient as we could in terms of how we constructed the house, and how it would be maintained over time. The end design was really a result of the least common denominator of these goals.

What's your favorite element of your home?:

Some of my favorite elements of our home are inspired by barn design. There is so much to learn from barns. A friend of mine once said it's hard to find a badly designed barn. A lot can be learned from studying barns in terms of cross ventilation and sun shading. Because we have a lot of glass, sun shading is important at different times of the day and different times of the year. Our low-tech version, which I love, is putting barn door tracks on the outside of the house and having sliding wood sunshades. They also lock into place so you can have security.

Biggest challenge in designing/building your home?:

Oh, where do I start? It took a lot of time researching the most efficient insulation and mechanical systems, materials that would last a long time with little maintenance that use the least amount of resources from the earth, the most efficient alternative energy solutions, systems for water conservation. Once we found the systems we wanted to use, it took time to find the best distributors, and figure out the best way to put it all together. Kevin was amazing in the process. He found great sources, but it took time. So, as we started to do the identical house for others, but using off-site technology, we were able to provide a solution where others can have the same beautiful and eco-friendly end result using the 5-ecoprinciples, but without having to go through the pain and time it took us.

What do you friends say about your home?:

I want one! And the great news is that they can have one. In fact, the second Glidehouse ever built was for a couple that have become good friends. Our house was built on site, but I decided to run an experiment with the second one and have it built in a factory and then compare the results. Factory built won out overwhelmingly — it saved time, cut down on waste and resources, and delivered a stronger product with more precision work.

What are some green things about your home that people might not notice at first glance?:

Most of the green aspects of my home aren't glaringly obvious when you step inside. Sure you'll see the solar panels on the outside and you might even notice the rainwater catchment system, but all of the green materials we use are beautiful in their own right. I think that's still an unfortunate misconception about green design — that somehow it means you're creating your home with recycled tires, or living in a yurt.

What was your biggest indulgence in designing your home?:

Outdoor rooms. At first, they felt like an indulgence, but now I realize that they were quite important to make the house feel larger than it is. Even in months when we can't literally use the outdoor rooms, we can see them, and there is still this sense of extending the space, connecting with the outdoors. I wanted no space left unused, including the space on top of the garage, that we made into a deck.

The other "indulgence" was the corten steel siding. This is a material that I absolutely love. It is a rusting steel that has oxides that allow it to rust, and then discontinue the rusting process. This means we will have absolutely zero maintenance with the siding of the house (no repainting, or refinishing in the future ) Plus, it makes the house visually nestle into the landscape. This is a material that a lot of sculptors use (like Richard Serra). It is so lovely.

Best advice you'd give to someone trying to green their home?:

Make choices that deliver the greatest bang for the buck. Swap out incandescent bulbs for CFLs or LEDs. Be aware of all the opportunities to conserve water in your home. For example, I just installed a terrific gray water system for my toilet, which is significantly cutting down on my water consumption. It takes an afternoon to install and it only costs about $200 (Aqus). A rainwater catchment system is another great way to cut down on water consumption but still keep your garden green (literally!).